1. Field of the Invention
The present invention relates to an irrigation/aspiration apparatus which supplies an irrigation liquid (fluid) to a surgical site and aspirates the supplied liquid with eliminated tissue.
2. Description of Related Art
A conventional irrigation/aspiration apparatus is known which supplies (infuses) an irrigation liquid to a surgical site (a diseased part), and also aspirates and removes the supplied liquid with tissue eliminated from the surgical site. Particularly in the field of ophthalmology, the apparatus is used in cataract surgery, vitreos surgery and the like. In the cataract surgery, the apparatus aspirates eliminated tissue together with an irrigation liquid supplied to a surgical site of a patient's eye using a handpiece with a chip having an aspiration hole mounted on its tip, and discharges the aspirated liquid with the eliminated tissue from one end of an aspiration tube.
Incidentally, this kind of apparatus must have a system for controlling aspiration pressure during surgery. Therefore, an apparatus is well known in which an aspiration pressure detecting system having a pressure sensor and a connecting part are provided midway along the aspiration tube and in which the pressure sensor detects the aspiration pressure via the connecting part. However, since the pressure sensor detects the aspiration pressure in the aspiration tube directly, the liquid with the eliminated tissue aspirated from the patient's eye sometimes enters the aspiration pressure detecting system. When the aspirated liquid enters the aspiration pressure detecting system, bacteria propagate there, and it is not free from the possibility that the liquid including the bacteria flows back into the aspiration tube and causes in-hospital infection during the surgery. As a remedy for that, a method is applied where a disposable filter and the like are attached to the connecting part between the pressure sensor and the aspiration tube, so that the bacteria are prevented from moving.
However, the method of attaching the filter and the like to the connecting part makes it difficult to detect the aspiration pressure accurately because of resistance of the filter, and clogging caused by the tissue and other objects which are adhered to the filter.
In addition, at the time of detaching the aspiration tube from the apparatus, the liquid with the eliminated tissue aspirated from the patient's eye might flow outs and the apparatus and its periphery possibly become dirty.